Allow elevators to sort/merge discard requests
But blkdev_issue_discard() still emits requests which are interpreted as
soft barriers, because naïve callers might otherwise issue subsequent
writes to those same sectors, which might cross on the queue (if they're
reallocated quickly enough).
Callers still _can_ issue non-barrier discard requests, but they have to
take care of queue ordering for themselves.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 727886d..e9eb35c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -541,7 +541,7 @@
#define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
-#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
+#define blk_account_rq(rq) (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq)))
#define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
#define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
@@ -598,7 +598,8 @@
#define RQ_NOMERGE_FLAGS \
(REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
#define rq_mergeable(rq) \
- (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
+ (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
+ (blk_discard_rq(rq) || blk_fs_request((rq))))
/*
* q->prep_rq_fn return values